Legionella dumoffii Tex-KL Mutated in an Operon Homologous to traC-traD is Defective in Epithelial Cell Invasion  

作　　者：QIN Tian Iida Ken-ichiro REN Hong Yu ZHOU Hai Jian Shin-ichi Yoshida 

机构地区：[1]State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, beijing 102206, China [2]Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Hangzhou 310003, Zhejiang, China [3]Departments of Bacteriology, Faculty of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka 812-8582, Japan

出　　处：《Biomedical and Environmental Sciences》2016年第6期424-434,共11页生物医学与环境科学（英文版）

基　　金：supported by the National Natural Scientific Foundation(No.81201251)from the Ministry of Science and Technology of the People’s Republic of China;the Priority Project on Infectious Disease Control and Prevention(No.2012ZX10004215 and 2013ZX10004-610-007)from the Ministry of Health and the Ministry of Science and Technology of the People’s Republic of China;the Science Foundation for the State Key Laboratory for Infectious Disease Prevention and Control from China(Grant No.2015SKLID508 and 2011SKLID202)

摘　　要：Objective To understand the mechanism of invasion by Legionella dumoffii. Methods The L. dumoffii strain Tex-KL was mutated using the Tn903 derivative, Tn903 d IIlac Z. After screening 799 transposon insertion mutants, we isolated one defective mutant. We then constructed the gene-disrupted mutant, KL16, and studied its invasion of and intracellular growth in He La and A549 cells, and in A/J mice survival experiments. The structure of traC-traD operon was analyzed by RT-PCR. Results The transposon insertion was in a gene homologous to Salmonella typhi tra C, which is required for the assembly of F pilin into the mature F pilus structure and for conjugal DNA transmission. Results from RT-PCR suggested that the traC-traD region formed an operon. We found that when the tra C gene was disrupted, invasion and intracellular growth of L. dumoffii Tex-KL were impaired in human epithelial cells. When mice were infected by intranasal inoculation with a tra C deficient mutant, their survival significantly increased when compared to mice infected with the wild-type strain. Conclusion Our results indicated that the traC-traD operon is required for the invasion and intracellular growth abilities of L. dumoffii Tex-KL in epithelial cells.Objective To understand the mechanism of invasion by Legionella dumoffii. Methods The L. dumoffii strain Tex-KL was mutated using the Tn903 derivative, Tn903 d IIlac Z. After screening 799 transposon insertion mutants, we isolated one defective mutant. We then constructed the gene-disrupted mutant, KL16, and studied its invasion of and intracellular growth in He La and A549 cells, and in A/J mice survival experiments. The structure of traC-traD operon was analyzed by RT-PCR. Results The transposon insertion was in a gene homologous to Salmonella typhi tra C, which is required for the assembly of F pilin into the mature F pilus structure and for conjugal DNA transmission. Results from RT-PCR suggested that the traC-traD region formed an operon. We found that when the tra C gene was disrupted, invasion and intracellular growth of L. dumoffii Tex-KL were impaired in human epithelial cells. When mice were infected by intranasal inoculation with a tra C deficient mutant, their survival significantly increased when compared to mice infected with the wild-type strain. Conclusion Our results indicated that the traC-traD operon is required for the invasion and intracellular growth abilities of L. dumoffii Tex-KL in epithelial cells.

关 键 词：L. dumoffii Tex-KL traC-traD operon Invasion ability Epithelial cells 

分 类 号：R378[医药卫生—病原生物学]